This invention relates in general to telecommunications test equipment and, more particularly, to an apparatus for line state analysis in an asynchronous digital subscriber line system.
The use of computers and the amount of data stored on computers has increased each year. Along with the increased use of computers has come an increased need for allowing those computers to communicate. This has led to an increased utilization of existing telecommunication systems for computer-to-computer communication. Methods for increasing the amount of data that can be communicated over existing telecommunication systems have been developed to answer the need for increasing computer-to-computer communication.
Asynchronous digital subscriber line (ADSL) modems are one method that has been developed for communicating increased amounts of data over existing telecommunication systems. ADSL utilizes a two stage protocol involving a pre-training stage and a training stage to establish communication between a pair of ADSL modems. The two ADSL modems are known as the R-modem and the C-modem in the industry. At initialization the R-modem enters an activate request mode and the C-modem enters an idle mode. In the pre-training stage two ADSL modems establish communication using a lock-step series of signals. The first signal is an ACTIVATE REQUEST signal, followed by a C-ACT signal, then an R-ACT signal, and finally a C-REVEILLE signal. After the C-REVEILLE signal the modems enter the training stage.
The development and use of ADSL modems has created many challenges. One such challenge is determining why two ADSL modems are not properly communicating. Currently, when an operator is trying to repair a dead modem or modems, the operator has no knowledge of where to start looking for the problem, because the problem could stem from a variety of sources, such as the modems themselves or the lines connecting the modems. Traditional methods of detecting these problems required the deployment of oscilloscopes, frequency counters, and other complex equipment and often involved opening up the modems themselves.
From the foregoing, it may be appreciated that a need has arisen for an apparatus for determination of line state and initialization progress between modems, so as to achieve more efficient testing.
According to one form of the present invention, an apparatus is provided to address this need, and involves a communications line interface which can be operatively coupled to a communications line, and a frequency detection circuit operatively coupled to the interface and having an output. The frequency detection circuit is operable to detect through the interface an occurrence of each of a plurality of predetermined frequencies on the communications line and to provide to the output an indication of each such frequency which has been detected.
According to another form of the present invention, a self-contained line state analyzer includes: a communications line interface which can be operatively coupled to and detect signals on a communications line; an operator information portion; and a circuit portion which is operatively coupled to the interface and the operator information portion. The circuit portion is operative to automatically detect through the interface the occurrence of a signal at a predetermined frequency, and to automatically provide on the operator information portion an operator perceptible indication of whether a signal at the predetermined frequency has been detected.